4.6is (Star Spoke 87) wheel weights?

[Teutonaddict]

I really dig the clean five-spoke look of the 20" Star Spoke 87 OE wheels on the 4.6is.

When I mentioned to my sales guy that I was planning the swap, he said he thought they were significantly heavier than the seven-spoke Style 168 that were OE on my '05 4.8is. Then again, he doesn't care for mods of any type...

Does anybody know the wheel weights of the 20" 4.6 wheels?

Thanks in advance for your help. You're contributing to the delinquency of a new X5 owner...

-Dave

[Hans_ACS]

yes, but only in kilograms

Front : 12 kg
Rear : 12.6 kg

(this is for the wheels only, tires not included).

I once measured replicas too, and they are much more heavier :

front : 14 kg
rear : 15 kg

[DinanX5]

Thanks Hans - good to know... I've been wondering this myself. (By the way, in English, this equates to 26.46/ 27.78 lbs.)

Anyone know about the 168s?

[Teutonaddict]

Originally Posted by Hans_ACS

yes, but only in kilograms

Front : 12 kg
Rear : 12.6 kg

Dank u, Hans. Danke schön!

That's quite interesting. But now I'm a little confused, as the one weight I've seen listed for my OE Style 168s makes them heavier than the 87's. Confusing only in it contradicts my salesman who's pretty sharp most of the time.

I've seen the 168's reported as 17kg (37.5 lb) front and 17.9kg (39.5 lb) rears in this For Sale thread (http://www.xoutpost.com/showthread.php?t=7617)

So...

Does anybody have different weights for the factory Style 168 wheels?

As always, thanks for the assistance!
-Dave

[DINANM3]

i seriously dought there is that much difference in weight between the 87s and the 168s. why would there be. if anything the 168s would be slightly heavier because of more spokes

[Teutonaddict]

Originally Posted by DinanX5

(By the way, in English, this equates to 26.46/ 27.78 lbs.)

Thanks, Aaron. BTW, those would be some of the lightest 20" I've come across. Those are within a pound or two of my lightweight Kinesis forged three-pc wheels that I had in 18" sizes on my M5.

[DinanX5]

Yes, that is very light!! If these numbers are correct, then the 87s will definitely be a better performing wheel than the 168s... I would think that 11+ lbs per wheel is enough of a rotational mass difference to feel even on the big 'ole X5.

By the way, I've never met a car sales guy that has his facts and figures straight...

[ricky.agrawal]

11lb per wheel is plenty. Isn't it for every four lb of unsprung it's like feeling 1hp?

That means about three hp * 4 = 12hp 'freed' up. Even if you don't feel it accelerating or breaking, you'll feel it turning.

[Teutonaddict]

Originally Posted by DINANM3

i seriously doubt there is that much difference in weight between the 87s and the 168s. why would there be. if anything the 168s would be slightly heavier because of more spokes

I agree with your first statement--I doubt BMW would 'upgrade' or change to a factory wheel that's 40+% heavier than the one it replaces... Looks like I'm going to have to visit the dealer and take some first-hand measurements.

The more spokes = more weight principle only works if the spokes are of the same size and structure on both wheels. So I could see cases where the inverse were true.

Oh well. More to come!

[ricky.agrawal]

The more spokes = more weight also only holds true if the rims are same density and a lot of other factors.

Aren't the stock BMW rims made by gravity cast? If that's the case, I don't think they'll be uniformly dense all the way around.

Do you think that the 168's were reported with tires and the 87's were reported without tires?
I just did some searching, seems like average tires are in the 20ish pound range.

Style 87
Front: 26.46
Rear: 27.78

Style 168
Front: 37.5
Rear: 39.5

If the Style 168's had tires on them, and the 87's didn't, that means the Style 168's are 17.5 / 19.5.. which makes my theory very unreasonable.

BTW: If you compare the weights of the Style 87 rims listed above, to rims on www.iforged.com that means that these one piece OE BMW rims (I have no idea how they are constructed) weigh very close to custom three piece forged rims. Cool!